Ask HN: Has anyone successfully been able to completely quit using Google?

Yes. As far as I can tell. Google lost me the day they shut down Reader. There are plenty of alternatives as long as you're not forced by your job or a particular client into using their services.

One thing I'd still like to achieve is to find a permanent solution for avoiding communication with people who use Gmail. Strong-arming them into a new e-mail service is a non-starter.

This is also true of other services. While Facebook is famous for its shadow profiles, equally (if not more) concerning are DNA ancestry services - effectively, if any of your relatives submit to these tests, your DNA can be easily matched even if you have never used their services.

you can.. It's an adjustment.

I have my own website, to which I run a mail server. It's a bit of work, but worth it, unless you aren't familiar with sysadmin or Linux, you can check out proton mail or several others out there. You won't get all the fun stuff, like Google adding things automatically to your calendar or trying to give replies for you to emails it might know better. You also miss out on ads from anything you've recently searched or said something in an email and strangely you get ads for similar products now.

Use davical for contacts and calendar.

my android phone, I only use Fdroid or yalp anonymous for apps. I do have a generic account on an older phone I develop on that if there is something I want to purchase I buy, then transfer the apk to my actual phone. You'll find pretty quickly which devs hate you as they enforce play services.

Checking all the things, you'll find can be done over browser, though more and more sites are pushing to force compliance & use their app.

You'll find that it can become (and has been intentionally I'm sure) pretty painful outside their apps, so might spend less time doing those things. Be prepared, you might get more productive or maybe You'll take up a bad habit like smoking

https://switching.social has some recommendations for those wanting to leave google and other large tech companies that have become pervasive.

Nope, Google Maps is sticky. I've tried alternatives and just haven't had any luck. OsmAnd (Open Street Maps on Android) is good for plenty, but not driving.